Why attacking the Home Fleet would squander the U-boat arm

What if Germany used its U-boat fleet against the British Home Fleet instead of commerce shipping?

The Royal Navy would welcome the change because fleet destroyers, aircraft, cruiser-borne aviation, and base hydrophones concentrated defenses around the force Germany was choosing to approach.

Commerce raiding forced Britain to protect a vast and dispersed shipping system; sending U-boats directly toward the Home Fleet would concentrate them against prepared escorts, aircraft, and sensors. The panel notes that Scapa Flow was an important exception with inadequate defenses, connecting the gap to interwar funding decisions. The exchange shows why target selection, not just submarine numbers, determines strategic effectiveness.